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Encinas-Valero M, Esteban R, Hereş AM, Becerril JM, García-Plazaola JI, Artexe U, Vivas M, Solla A, Moreno G, Curiel Yuste J. Photoprotective compounds as early markers to predict holm oak crown defoliation in declining Mediterranean savannahs. TREE PHYSIOLOGY 2022; 42:208-224. [PMID: 33611551 DOI: 10.1093/treephys/tpab006] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/04/2021] [Indexed: 06/12/2023]
Abstract
Dehesas, human-shaped savannah-like ecosystems, where the overstorey is mainly dominated by the evergreen holm oak (Quercus ilex L. subsp. ballota (Desf.) Samp.), are classified as a global conservation priority. Despite being Q. ilex a species adapted to the harsh Mediterranean environmental conditions, recent decades have witnessed worrisome trends of climate-change-induced holm oak mortality. Holm oak decline is evidenced by tree vigour loss, gradual defoliation and ultimately, death. However, before losing leaves, trees undergo leaf-level physiological adjustments in response to stress that may represent a promising field to develop biochemical early markers of holm oak decline. This study explored holm oak photoprotective responses (pigments, tocopherols and photosynthetic performance) in 144 mature holm oak trees with different health statuses (i.e., crown defoliation percentages) from healthy to first-stage declining individuals. Our results indicate differential photochemical performance and photoprotective compounds concentration depending on the trees' health status. Declining trees showed higher energy dissipation yield, lower photochemical efficiency and enhanced photoprotective compounds. In the case of total violaxanthin cycle pigments (VAZ) and tocopherols, shifts in leaf contents were significant at very early stages of crown defoliation, even before visual symptoms of decline were evident, supporting the value of these biochemical compounds as early stress markers. Linear mixed-effects models results showed an acute response, both in the photosynthesis performance index and in the concentration of foliar tocopherols, during the onset of tree decline, whereas VAZ showed a more gradual response along the defoliation gradient of the crown. These results collectively demonstrate that once a certain threshold of leaf physiological damage is surpassed, that leaf cannot counteract oxidative stress and progressive loss of leaves occurs. Therefore, the use of both photosynthesis performance indexes and the leaf tocopherols concentration as early diagnostic tools might predict declining trends, facilitating the implementation of preventive measures to counteract crown defoliation.
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Affiliation(s)
- Manuel Encinas-Valero
- BC3-Basque Centre for Climate Change, Scientific Campus of the University of the Basque Country, 48940 Leioa, Bizkaia, Spain
| | - Raquel Esteban
- Department of Plant Biology and Ecology, University of Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Bizkaia, Spain
| | - Ana-Maria Hereş
- BC3-Basque Centre for Climate Change, Scientific Campus of the University of the Basque Country, 48940 Leioa, Bizkaia, Spain
- Department of Forest Sciences, Transilvania University of Braşov, Sirul Beethoven-1, 500123 Braşov, Romania
| | - José María Becerril
- Department of Plant Biology and Ecology, University of Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Bizkaia, Spain
| | - José Ignacio García-Plazaola
- Department of Plant Biology and Ecology, University of Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Bizkaia, Spain
| | - Unai Artexe
- Department of Plant Biology and Ecology, University of Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Bizkaia, Spain
| | - María Vivas
- Faculty of Forestry, Institute for Dehesa Research (INDEHESA), University of Extremadura, Avenida Virgen del Puerto 2, 10600 Plasencia, Spain
| | - Alejandro Solla
- Faculty of Forestry, Institute for Dehesa Research (INDEHESA), University of Extremadura, Avenida Virgen del Puerto 2, 10600 Plasencia, Spain
| | - Gerardo Moreno
- Faculty of Forestry, Institute for Dehesa Research (INDEHESA), University of Extremadura, Avenida Virgen del Puerto 2, 10600 Plasencia, Spain
| | - Jorge Curiel Yuste
- BC3-Basque Centre for Climate Change, Scientific Campus of the University of the Basque Country, 48940 Leioa, Bizkaia, Spain
- IKERBASQUE, Basque Foundation for SciencePlaza Euskadi 548009 Bilbao, Bizkaia, Spain
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2
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Monitoring Drought through the Lens of Landsat: Drying of Rivers during the California Droughts. REMOTE SENSING 2021. [DOI: 10.3390/rs13173423] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Water scarcity during severe droughts has profound hydrological and ecological impacts on rivers. However, the drying dynamics of river surface extent during droughts remains largely understudied. Satellite remote sensing enables surveys and analyses of rivers at fine spatial resolution by providing an alternative to in-situ observations. This study investigates the seasonal drying dynamics of river extent in California where severe droughts have been occurring more frequently in recent decades. Our methods combine the use of Landsat-based Global Surface Water (GSW) and global river bankful width databases. As an indirect comparison, we examine the monthly fractional river extent (FrcSA) in 2071 river reaches and its correlation with streamflow at co-located USGS gauges. We place the extreme 2012–2015 drought into a broader context of multi-decadal river extent history and illustrate the extraordinary change between during- and post-drought periods. In addition to river extent dynamics, we perform statistical analyses to relate FrcSA with the hydroclimatic variables obtained from the National Land Data Assimilation System (NLDAS) model simulation. Results show that Landsat provides consistent observation over 90% of area in rivers from March to October and is suitable for monitoring seasonal river drying in California. FrcSA reaches fair (>0.5) correlation with streamflow except for dry and mountainous areas. During the 2012–2015 drought, 332 river reaches experienced their lowest annual mean FrcSA in the 34 years of Landsat history. At a monthly scale, FrcSA is better correlated with soil water in more humid areas. At a yearly scale, summer mean FrcSA is increasingly sensitive to winter precipitation in a drier climate; and the elasticity is also reduced with deeper ground water table. Overall, our study demonstrates the detectability of Landsat on the river surface extent in an arid region with complex terrain. River extent in catchments of deficient water storage is likely subject to higher percent drop in a future climate with longer, more frequent droughts.
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Pouteau R, Biurrun I, Brunel C, Chytrý M, Dawson W, Essl F, Fristoe T, Haveman R, Hobohm C, Jansen F, Kreft H, Lenoir J, Lenzner B, Meyer C, Moeslund JE, Pergl J, Pyšek P, Svenning J, Thuiller W, Weigelt P, Wohlgemuth T, Yang Q, van Kleunen M. Potential alien ranges of European plants will shrink in the future, but less so for already naturalized than for not yet naturalized species. DIVERS DISTRIB 2021. [DOI: 10.1111/ddi.13378] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Robin Pouteau
- Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation Taizhou University Taizhou China
- AMAP, Univ. Montpellier IRD CIRAD CNRS INRAMontpellier Cedex 05 France
| | - Idoia Biurrun
- Department of Plant Biology and Ecology Faculty of Science and Technology University of the Basque Country UPV/EHU Bilbao Spain
| | - Caroline Brunel
- Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation Taizhou University Taizhou China
- IRDIPME Montpellier France
| | - Milan Chytrý
- Department of Botany and Zoology Faculty of Science Masaryk University Brno Czech Republic
| | - Wayne Dawson
- Department of Biosciences Durham University Durham UK
| | - Franz Essl
- Bioinvasions, Global Change, Macroecology Group Department of Botany and Biodiversity Research University of Vienna Vienna Austria
| | - Trevor Fristoe
- Ecology Department of Biology University of Konstanz Konstanz Germany
| | - Rense Haveman
- Central Government Real Estate Agency of the Dutch Ministry of the Interior and Kingdom Relations, Exterior Space Nature Department Wageningen The Netherlands
| | - Carsten Hobohm
- Ecology and Environmental Education Working Group University of Flensburg (EUF) Flensburg Germany
| | - Florian Jansen
- Faculty of Agricultural and Environmental Sciences University of Rostock Rostock Germany
| | - Holger Kreft
- Biodiversity, Macroecology & Biogeography University of Göttingen Göttingen Germany
- Centre of Biodiversity and Sustainable Land Use (CBL) University of Göttingen Germany
| | - Jonathan Lenoir
- UR “Ecologie et Dynamique des Systèmes Anthropisés” (EDYSAN UMR 7058 CNRS) Université de Picardie Jules Verne Amiens Cedex 1 France
| | - Bernd Lenzner
- Bioinvasions, Global Change, Macroecology Group Department of Botany and Biodiversity Research University of Vienna Vienna Austria
| | - Carsten Meyer
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Leipzig Germany
- Institute of Biology Leipzig University Leipzig Germany
- Institute for Geosciences and Geography Martin Luther University Halle‐Wittenberg Halle (Saale) Germany
| | | | - Jan Pergl
- Institute of Botany Department of Invasion Ecology Czech Academy of Sciences Průhonice Czech Republic
| | - Petr Pyšek
- Institute of Botany Department of Invasion Ecology Czech Academy of Sciences Průhonice Czech Republic
- Department of Ecology Faculty of Science Charles University Prague Czech Republic
| | - Jens‐Christian Svenning
- Center for Biodiversity Dynamics in a Changing World (BIOCHANGE) and Section for Ecoinformatics and Biodiversity, Department of Biology Aarhus University Aarhus C Denmark
| | - Wilfried Thuiller
- Univ. Grenoble Alpes Univ. Savoie Mont Blanc, CNRS, LECA Grenoble France
| | - Patrick Weigelt
- Biodiversity, Macroecology & Biogeography University of Göttingen Göttingen Germany
- Campus Institute Data Science Göttingen Germany
| | - Thomas Wohlgemuth
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL Birmensdorf Switzerland
| | - Qiang Yang
- Ecology Department of Biology University of Konstanz Konstanz Germany
| | - Mark van Kleunen
- Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation Taizhou University Taizhou China
- Ecology Department of Biology University of Konstanz Konstanz Germany
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4
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Deepening Rooting Depths Improve Plant Water and Carbon Status of a Xeric Tree during Summer Drought. FORESTS 2019. [DOI: 10.3390/f10070592] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Exploring the effects of drought on trees of different sizes is an important research topic because the size-dependent mortality pattern of the major dominant species significantly affects the structure and function of plant communities. Here we studied the physiological performance and non-structural carbohydrates (NSCs) dynamics of a small xeric tree species, Haloxylon ammodendron (C.A.Mey.) of different tree size with varying rooting depth, during summer drought. We measured predawn (Ψpd) and midday (Ψm) leaf water potential, osmotic potential at saturated turgor (π100), and turgor lost point (Ψtlp), stomatal conductance (gs) at noon, maximum photochemical efficiency of photosystem II (Fv/Fm) in the morning, and NSCs concentration, from June–September. Our results demonstrated that the summer drought reduces the overall performance of physiological traits of the small young trees more than the larger adult trees. Ψpd, gs and Fv/Fm dropped larger in the small-diameter groups than the larger diameter groups. Substantial osmotic adjustments were observed in small size individuals (with lower π100 and Ψtlp) to cope with summer drought. Furthermore, mean concentration of NSCs for the leaf and shoot were higher in September than in July in every basal stem diameter classes suggested the leaf and shoot acted as reserve for NSC. However the root NSCs concentrations within each basal stem diameter class exhibited less increase in September than in the July. At the same time, the small young tress had lower root NSCs concentrations than the larger adult tree in both July and September. The contrasting root NSC concentrations across the basal stem diameter classes indicated that the roots of smaller trees may be more vulnerable to carbon starvation under non-lethal summer drought. The significant positive relationship between rooting depth and physiological traits & root NSCs concentration emphasize the importance of rooting depth in determining the seasonal variation of water status, gas exchange and NSCs.
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Albrich K, Rammer W, Thom D, Seidl R. Trade-offs between temporal stability and level of forest ecosystem services provisioning under climate change. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1884-1896. [PMID: 30055058 PMCID: PMC6378588 DOI: 10.1002/eap.1785] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 04/11/2018] [Accepted: 07/11/2018] [Indexed: 05/20/2023]
Abstract
The ability of forests to continuously provide ecosystem services (ES) is threatened by rapid changes in climate and disturbance regimes. Consequently, these changes present a considerable challenge for forest managers. Management of forests often focuses on maximizing the level of ES provisioning over extended time frames (i.e., rotation periods of more than 100 yr). However, temporal stability is also crucial for many ES, for example, in the context of a steady provisioning of resources to the industry, or the protection of human infrastructure against natural hazards. How temporal stability and the level of ES provisioning are related is of increasing interest, particularly since changing climate and disturbance regimes amplify temporal variability in forest ecosystems. In this simulation study, we investigated whether forest management can simultaneously achieve high levels and temporal stability of ES provisioning. Specifically, we quantified (1) trade-offs between ES stability and level of ES provisioning, and (2) the effect of tree species diversity on ES stability. Simulating a wide range of future climate scenarios and management strategies, we found a negative relationship between temporal stability and level of ES provisioning for timber production, carbon cycling, and site protection in a landscape in the Austrian Alps. Tree species diversity had a predominantly positive effect on ES stability. We conclude that attempts to maximize the level of ES provisioning may increase its temporal variability, and thus threaten the continuity of ES supply. Consequently, considerations of stability need to be more explicitly included in forest management planning under increasingly variable future conditions.
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Affiliation(s)
- Katharina Albrich
- Institute of SilvicultureUniversity of Natural Resources and Life Sciences (BOKU) ViennaPeter Jordan Straße 821190WienAustria
| | - Werner Rammer
- Institute of SilvicultureUniversity of Natural Resources and Life Sciences (BOKU) ViennaPeter Jordan Straße 821190WienAustria
| | - Dominik Thom
- Institute of SilvicultureUniversity of Natural Resources and Life Sciences (BOKU) ViennaPeter Jordan Straße 821190WienAustria
- Present address:
Rubenstein School of Environment and Natural ResourcesUniversity of Vermont308i Aiken CenterBurlingtonVermont05405USA
| | - Rupert Seidl
- Institute of SilvicultureUniversity of Natural Resources and Life Sciences (BOKU) ViennaPeter Jordan Straße 821190WienAustria
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6
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Rogers BM, Solvik K, Hogg EH, Ju J, Masek JG, Michaelian M, Berner LT, Goetz SJ. Detecting early warning signals of tree mortality in boreal North America using multiscale satellite data. GLOBAL CHANGE BIOLOGY 2018; 24:2284-2304. [PMID: 29481709 DOI: 10.1111/gcb.14107] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 02/12/2018] [Indexed: 05/19/2023]
Abstract
Increasing tree mortality from global change drivers such as drought and biotic infestations is a widespread phenomenon, including in the boreal zone where climate changes and feedbacks to the Earth system are relatively large. Despite the importance for science and management communities, our ability to forecast tree mortality at landscape to continental scales is limited. However, two independent information streams have the potential to inform and improve mortality forecasts: repeat forest inventories and satellite remote sensing. Time series of tree-level growth patterns indicate that productivity declines and related temporal dynamics often precede mortality years to decades before death. Plot-level productivity, in turn, has been related to satellite-based indices such as the Normalized difference vegetation index (NDVI). Here we link these two data sources to show that early warning signals of mortality are evident in several NDVI-based metrics up to 24 years before death. We focus on two repeat forest inventories and three NDVI products across western boreal North America where productivity and mortality dynamics are influenced by periodic drought. These data sources capture a range of forest conditions and spatial resolution to highlight the sensitivity and limitations of our approach. Overall, results indicate potential to use satellite NDVI for early warning signals of mortality. Relationships are broadly consistent across inventories, species, and spatial resolutions, although the utility of coarse-scale imagery in the heterogeneous aspen parkland was limited. Longer-term NDVI data and annually remeasured sites with high mortality levels generate the strongest signals, although we still found robust relationships at sites remeasured at a typical 5 year frequency. The approach and relationships developed here can be used as a basis for improving forest mortality models and monitoring systems.
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Affiliation(s)
| | | | - Edward H Hogg
- Northern Forestry Centre, Canadian Forest Service, Natural Resources Canada, Edmonton, AB, Canada
| | - Junchang Ju
- Biospheric Science Laboratory (Code 618), NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Jeffrey G Masek
- Biospheric Science Laboratory (Code 618), NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Michael Michaelian
- Northern Forestry Centre, Canadian Forest Service, Natural Resources Canada, Edmonton, AB, Canada
| | - Logan T Berner
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Scott J Goetz
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
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7
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Kinzner M, Krapf P, Nindl M, Heussler C, Eisenkölbl S, Hoffmann AA, Seeber J, Arthofer W, Schlick‐Steiner BC, Steiner FM. Life-history traits and physiological limits of the alpine fly Drosophila nigrosparsa (Diptera: Drosophilidae): A comparative study. Ecol Evol 2018; 8:2006-2020. [PMID: 29468020 PMCID: PMC5817156 DOI: 10.1002/ece3.3810] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 11/27/2017] [Accepted: 12/11/2017] [Indexed: 11/11/2022] Open
Abstract
Interspecific variation in life-history traits and physiological limits can be linked to the environmental conditions species experience, including climatic conditions. As alpine environments are particularly vulnerable under climate change, we focus on the montane-alpine fly Drosophila nigrosparsa. Here, we characterized some of its life-history traits and physiological limits and compared these with those of other drosophilids, namely Drosophila hydei, Drosophila melanogaster, and Drosophila obscura. We assayed oviposition rate, longevity, productivity, development time, larval competitiveness, starvation resistance, and heat and cold tolerance. Compared with the other species assayed, D. nigrosparsa is less fecund, relatively long-living, starvation susceptible, cold adapted, and surprisingly well heat adapted. These life-history characteristics provide insights into invertebrate adaptations to alpine conditions which may evolve under ongoing climate change.
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Affiliation(s)
| | - Patrick Krapf
- Institute of EcologyUniversity of InnsbruckInnsbruckAustria
| | - Martina Nindl
- Institute of EcologyUniversity of InnsbruckInnsbruckAustria
| | | | | | - Ary A. Hoffmann
- School of BioSciencesBio21 InstituteUniversity of MelbourneParkvilleVic.Australia
| | - Julia Seeber
- Institute of EcologyUniversity of InnsbruckInnsbruckAustria
- Institute for Alpine EnvironmentEurac ResearchBozen/BolzanoItaly
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8
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Cobb RC, Ruthrof KX, Breshears DD, Lloret F, Aakala T, Adams HD, Anderegg WRL, Ewers BE, Galiano L, Grünzweig JM, Hartmann H, Huang CY, Klein T, Kunert N, Kitzberger T, Landhäusser SM, Levick S, Preisler Y, Suarez ML, Trotsiuk V, Zeppel MJB. Ecosystem dynamics and management after forest die-off: a global synthesis with conceptual state-and-transition models. Ecosphere 2017. [DOI: 10.1002/ecs2.2034] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- Richard C. Cobb
- Natural Resources Management & Environmental Sciences Department; California State Polytechnic University; San Luis Obispo California 93407 USA
| | - Katinka X. Ruthrof
- School of Veterinary and Life Sciences; Murdoch University; 90 South Street Perth Western Australia 6150 Australia
- Botanic Gardens and Parks Authority; Perth Western Australia 6005 Australia
| | - David D. Breshears
- School of Natural Resources and the Environment, and Department of Ecology and Evolutionary Biology; University of Arizona; 1064 East Lowell Street Tucson Arizona 85721 USA
| | - Francisco Lloret
- Center of Ecological Research and Forestry Applications (CREAF); Universitat Autònoma of Barcelona; Edifici C, Campus UAB, 08193 Bellaterra 26 Barcelona Spain
| | - Tuomas Aakala
- Department of Forest Sciences; University of Helsinki; Latokartanonkaari 7 Helsinki FI-00014 Finland
| | - Henry D. Adams
- Department of Plant Biology, Ecology, and Evolution; Oklahoma State University; 301 Physical Sciences Stillwater Oklahoma 74074 USA
| | | | - Brent E. Ewers
- Department of Botany and Program in Ecology and Wyoming EPSCoR; University of Wyoming; Laramie Wyoming 82071 USA
| | | | - José M. Grünzweig
- Robert H. Smith Faculty of Agriculture, Food and Environment; The Hebrew University of Jerusalem; P.O. Box 12 Rehovot Israel
| | - Henrik Hartmann
- Department of Biogeochemical Processes; Max-Planck Institute for Biogeochemistry; Hans Knöll Strasse 10 Jena 07745 Germany
| | - Cho-ying Huang
- Department of Geography; National Taiwan University; 1 Sec. 4, Roosevelt Road Taipei 10617 Taiwan
| | - Tamir Klein
- Weizmann Institute of Science; Rehovot 76100 Israel
| | - Norbert Kunert
- University of Freiburg; Tennenbacherstrasse 4 Freiburg 79106 Germany
| | - Thomas Kitzberger
- Departamento de Ecología; INIBIOMA-CONICET; Universidad Nacional del Comahue; Quintral 1250 Bariloche 8400 Argentina
| | - Simon M. Landhäusser
- Department of Renewable Resources; University of Alberta; Edmonton Alberta T6G 2E3 Canada
| | - Shaun Levick
- Department of Biogeochemical Processes; Max-Planck Institute for Biogeochemistry; Hans Knöll Strasse 10 Jena 07745 Germany
- Research Institute for the Environment and Livelihoods; Charles Darwin University; Darwin Northern Territory 0909 Australia
| | - Yakir Preisler
- Robert H. Smith Faculty of Agriculture, Food and Environment; The Hebrew University of Jerusalem; P.O. Box 12 Rehovot Israel
- Department of Earth and Planetary Science; Weizmann Institute of Science; Herzl St 234 Rehovot 7610001 Israel
| | - Maria L. Suarez
- INIBIOMA-Universidad Nacionaldel Comahue; Quintral 1250 Bariloche 8400 Argentina
| | - Volodymyr Trotsiuk
- Faculty of Forestry and Wood Sciences; Czech University of Life Sciences Prague; Kamycka 129 Prague 16521 Czech Republic
| | - Melanie J. B. Zeppel
- Faculty of Pharmacy; University of Sydney; Camperdown New South Wales 2006 Australia
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9
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Zhang Y, Xie JB, Li Y. Effects of increasing root carbon investment on the mortality and resprouting of Haloxylon ammodendron seedlings under drought. PLANT BIOLOGY (STUTTGART, GERMANY) 2017; 19:191-200. [PMID: 27696600 DOI: 10.1111/plb.12511] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 09/27/2016] [Indexed: 06/06/2023]
Abstract
Tree mortality induced by drought is one of the most complex processes in ecology. Although two mechanisms associated with water and carbon balance are proposed to explain tree mortality, outstanding problems still exist. Here, in order to test how the root system benefits survival and resprouting of Haloxylon ammodendron seedlings, we examined the various water- and carbon-related physiological indicators (shoot water potential, photosynthesis, dark respiration, hydraulic conductance and non-structural carbohydrates [NSC]) of H. ammodendron seedlings, which were grown in drought and control conditions throughout a grow season in greenhouse. The survival time of the seedling root system (died 70 days after drought) doubled the survival time of the shoot (died at 35 days). Difference in survival time between shoot and root resulted from sustained root respiration supported by increased NSC in roots under drought. Furthermore, investment into the root contributed to resprouting following drought. Based on these results, a death criterion is proposed for this species. The time sequence of major events indicated that drought shifted carbon allocation between shoot and root and altered the flux among different sinks (growth, respiration or storage). The interaction of water and carbon processes determined death or survival of droughted H. ammodendron seedlings. These findings revealed that the 'root protection' strategy is critical in determining survival and resprouting of this species, and provided insights into the effects of carbon and water dynamics on tree mortality.
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Affiliation(s)
- Y Zhang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang, China
- University of Chinese Academy of Sciences, Beijing, China
| | - J-B Xie
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang, China
- College of Life Science, Shihezi University, Shihezi, China
| | - Y Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang, China
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10
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Pendleton L, Comte A, Langdon C, Ekstrom JA, Cooley SR, Suatoni L, Beck MW, Brander LM, Burke L, Cinner JE, Doherty C, Edwards PET, Gledhill D, Jiang LQ, van Hooidonk RJ, Teh L, Waldbusser GG, Ritter J. Coral Reefs and People in a High-CO2 World: Where Can Science Make a Difference to People? PLoS One 2016; 11:e0164699. [PMID: 27828972 PMCID: PMC5102364 DOI: 10.1371/journal.pone.0164699] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 09/29/2016] [Indexed: 01/10/2023] Open
Abstract
REEFS AND PEOPLE AT RISK Increasing levels of carbon dioxide in the atmosphere put shallow, warm-water coral reef ecosystems, and the people who depend upon them at risk from two key global environmental stresses: 1) elevated sea surface temperature (that can cause coral bleaching and related mortality), and 2) ocean acidification. These global stressors: cannot be avoided by local management, compound local stressors, and hasten the loss of ecosystem services. Impacts to people will be most grave where a) human dependence on coral reef ecosystems is high, b) sea surface temperature reaches critical levels soonest, and c) ocean acidification levels are most severe. Where these elements align, swift action will be needed to protect people's lives and livelihoods, but such action must be informed by data and science. AN INDICATOR APPROACH Designing policies to offset potential harm to coral reef ecosystems and people requires a better understanding of where CO2-related global environmental stresses could cause the most severe impacts. Mapping indicators has been proposed as a way of combining natural and social science data to identify policy actions even when the needed science is relatively nascent. To identify where people are at risk and where more science is needed, we map indicators of biological, physical and social science factors to understand how human dependence on coral reef ecosystems will be affected by globally-driven threats to corals expected in a high-CO2 world. Western Mexico, Micronesia, Indonesia and parts of Australia have high human dependence and will likely face severe combined threats. As a region, Southeast Asia is particularly at risk. Many of the countries most dependent upon coral reef ecosystems are places for which we have the least robust data on ocean acidification. These areas require new data and interdisciplinary scientific research to help coral reef-dependent human communities better prepare for a high CO2 world.
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Affiliation(s)
- Linwood Pendleton
- Université de Bretagne Occidentale, UMR6308 AMURE, IUEM, Plouzané, France
| | - Adrien Comte
- Université de Bretagne Occidentale, UMR6308 AMURE, IUEM, Plouzané, France
| | - Chris Langdon
- RSMAS/MBE, University of Miami, Miami, Florida, United States of America
| | - Julia A. Ekstrom
- University of California Davis, Policy Institute for Energy, Environment and the Economy, Davis, California, United States of America
| | - Sarah R. Cooley
- Ocean Conservancy, Washington, D.C., United States of America
| | - Lisa Suatoni
- Natural Resources Defense Council, New York, New York, United States of America
| | - Michael W. Beck
- The Nature Conservancy and the University of California, Santa Cruz, Ocean Sciences, Santa Cruz, California, United States of America
| | - Luke M. Brander
- Institute for Environmental Studies, VU University, Amsterdam, The Netherlands
| | - Lauretta Burke
- World Resources Institute, Washington, D.C., United States of America
| | - Josh E. Cinner
- James Cook University, ARC Centre of Excellence for Coral Reef Studies, Townsville, Australia
| | - Carolyn Doherty
- Duke University, Durham, North Carolina, United States of America
| | - Peter E. T. Edwards
- Coral Reef Conservation Program, NOAA, Silver Spring, Maryland, United States of America
| | - Dwight Gledhill
- Ocean Acidification Program, NOAA, Silver Spring, Maryland, United States of America
| | - Li-Qing Jiang
- Cooperative Institute for Climate and Satellites, Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland, United States of America
| | - Ruben J. van Hooidonk
- NOAA Atlantic Oceanographic and Meteorological Laboratory, Ocean Chemistry and Ecosystems Division, Miami, Florida, United States of America
- Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, United States of America
| | - Louise Teh
- Institute for Oceans and Fisheries, The University of British Columbia, Vancouver, British Columbia, Canada
| | - George G. Waldbusser
- Oregon State University, College of Earth, Ocean, and Atmospheric Sciences, Corvallis, Oregon, United States of America
| | - Jessica Ritter
- National Wildlife Foundation, Washington, D.C., United States of America
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11
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Xu GQ, McDowell NG, Li Y. A possible link between life and death of a xeric tree in desert. JOURNAL OF PLANT PHYSIOLOGY 2016; 194:35-44. [PMID: 26968083 DOI: 10.1016/j.jplph.2016.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 06/05/2023]
Abstract
Understanding the interactions between drought and tree ontogeny or size remains an essential research priority because size-specific mortality patterns have large impacts on ecosystem structure and function, determine forest carbon storage capacity, and are sensitive to climatic change. Here we investigate a xerophytic tree species (Haloxylon ammodendron (C.A. Mey.)) with which the changes in biomass allocation with tree size may play an important role in size-specific mortality patterns. Size-related changes in biomass allocation, root distribution, plant water status, gas exchange, hydraulic architecture and non-structural carbohydrate reserves of this xerophytic tree species were investigated to assess their potential role in the observed U-shaped mortality pattern. We found that excessively negative water potentials (<-4.7MPa, beyond the P50leaf of -4.1MPa) during prolonged drought in young trees lead to hydraulic failure; while the imbalance of photoassimilate allocation between leaf and root system in larger trees, accompanied with declining C reserves (<2% dry matter across four tissues), might have led to carbon starvation. The drought-resistance strategy of this species is preferential biomass allocation to the roots to improve water capture. In young trees, the drought-resistance strategy is not well developed, and hydraulic failure appears to be the dominant driver of mortality during drought. With old trees, excess root growth at the expense of leaf area may lead to carbon starvation during prolonged drought. Our results suggest that the drought-resistance strategy of this xeric tree is closely linked to its life and death: well-developed drought-resistance strategy means life, while underdeveloped or overdeveloped drought-resistance strategy means death.
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Affiliation(s)
- Gui-Qing Xu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China
| | - Nate G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Yan Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China.
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12
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Moore GW, Edgar CB, Vogel JG, Washington-Allen RA, March RG, Zehnder R. Tree mortality from an exceptional drought spanning mesic to semiarid ecoregions. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2016; 26:602-11. [PMID: 27209798 DOI: 10.1890/15-0330] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Significant areas of the southern USA periodically experience intense drought that can lead to episodic tree mortality events. Because drought tolerance varies among species and size of trees, such events can alter the structure and function of terrestrial ecosystem in ways that are difficult to detect with local data sets or solely with remote-sensing platforms. We investigated a widespread tree mortality event that resulted from the worst 1-year drought on record for the state of Texas, USA. The drought affected ecoregions spanning mesic to semiarid climate zones and provided a unique opportunity to test hypotheses related to how trees of varying genus and size were affected. The study was based on an extensive set of 599 distributed plots, each 0.16 ha, surveyed in the summer following the drought. In each plot, dead trees larger than 12.7 cm in diameter were counted, sized, and identified to the genus level. Estimates of total mortality were obtained for each of 10 regions using a combination of design-based estimators and calibrated remote sensing using MODIS 1-yr change in normalized difference vegetation index products developed by the U.S. Forest Service. As compared with most of the publicized extreme die-off events, this study documents relatively low rates of mortality occurring over a very large area. However, statewide, regional tree mortality was massive, with an estimated 6.2% of the live trees perishing, nearly nine times greater than normal annual mortality. Dead tree diameters averaged larger than the live trees for most ecoregions, and this trend was most pronounced in the wetter climate zones, suggesting a potential re-ordering of species dominance and downward trend in tree size that was specific to climatic regions. The net effect on carbon storage was estimated to be a redistribution of 24-30 Tg C from the live tree to dead tree carbon pool. The dead tree survey documented drought mortality in more than 29 genera across all regions, and surprisingly, drought resistant and sensitive species fared similarly in some regions. Both angiosperms and gymnosperms were affected. These results highlight that drought-driven mortality alters forest structure differently across climatic regions and genera.
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13
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Millar CI, Stephenson NL. Temperate forest health in an era of emerging megadisturbance. Science 2015; 349:823-6. [DOI: 10.1126/science.aaa9933] [Citation(s) in RCA: 537] [Impact Index Per Article: 59.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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14
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Allen CD, Breshears DD, McDowell NG. On underestimation of global vulnerability to tree mortality and forest die-off from hotter drought in the Anthropocene. Ecosphere 2015. [DOI: 10.1890/es15-00203.1] [Citation(s) in RCA: 1345] [Impact Index Per Article: 149.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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15
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Dorman M, Svoray T, Perevolotsky A, Moshe Y, Sarris D. What determines tree mortality in dry environments? A multi-perspective approach. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2015; 25:1054-71. [PMID: 26465042 DOI: 10.1890/14-0698.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Forest ecosystems function under increasing pressure due to global climate changes, while factors determining when and where mortality events will take place within the wider landscape are poorly understood. Observational studies are essential for documenting forest decline events, understanding their determinants, and developing sustainable management plans. A central obstacle towards achieving this goal is that mortality is often patchy across a range of spatial scales, and characterized by long-term temporal dynamics. Research must therefore integrate different methods, from several scientific disciplines, to capture as many relevant informative patterns as possible. We performed a landscape-scale assessment of mortality and its determinants in two representative Pinus halepensis planted forests from a dry environment (~300 mm), recently experiencing an unprecedented sequence of two severe drought periods. Three data sources were integrated to analyze the spatiotemporal variation in forest performance: (1) Normalized Difference Vegetation Index (NDVI) time-series, from 18 Landsat satellite images; (2) individual dead trees point-pattern, based on a high-resolution aerial photograph; and (3) Basal Area Increment (BAI) time-series, from dendrochronological sampling in three sites. Mortality risk was higher in older-aged sparse stands, on southern aspects, and on deeper soils. However, mortality was patchy across all spatial scales, and the locations of patches within "high-risk" areas could not be fully explained by the examined environmental factors. Moreover, the analysis of past forest performance based on NDVI and tree rings has indicated that the areas affected by each of the two recent droughts do not coincide. The association of mortality with lower tree densities did not support the notion that thinning semiarid forests will increase survival probability of the remaining trees when facing extreme drought. Unique information was obtained when merging dendrochronological and remotely sensed performance indicators, in contrast to potential bias when using a single approach. For example, dendrochronological data suggested highly resilient tree growth, since it was based only on the "surviving" portion of the population, thus failing to identify past demographic changes evident through remote sensing. We therefore suggest that evaluation of forest resilience should be based on several metrics, each suited for detecting transitions at a different level of organization.
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16
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Dickman LT, McDowell NG, Sevanto S, Pangle RE, Pockman WT. Carbohydrate dynamics and mortality in a piñon-juniper woodland under three future precipitation scenarios. PLANT, CELL & ENVIRONMENT 2015; 38:729-39. [PMID: 25159277 DOI: 10.1111/pce.12441] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 08/07/2014] [Indexed: 05/16/2023]
Abstract
Drought-induced forest mortality is an increasing global problem with wide-ranging consequences, yet mortality mechanisms remain poorly understood. Depletion of non-structural carbohydrate (NSC) stores has been implicated as an important mechanism in drought-induced mortality, but experimental field tests are rare. We used an ecosystem-scale precipitation manipulation experiment to evaluate leaf and twig NSC dynamics of two co-occurring conifers that differ in patterns of stomatal regulation of water loss and recent mortality: the relatively desiccation-avoiding piñon pine (Pinus edulis) and the relatively desiccation-tolerant one-seed juniper (Juniperus monosperma). Piñon pine experienced 72% mortality after 13-25 months of experimental drought and juniper experienced 20% mortality after 32-47 months. Juniper maintained three times more NSC in the foliage than twigs, and converted NSC to glucose and fructose under drought, consistent with osmoregulation requirements to maintain higher stomatal conductance during drought than piñon. Despite these species differences, experimental drought caused decreased leaf starch content in dying trees of both species (P < 0.001). Average dry-season leaf starch content was also a good predictor of drought-survival time for both species (R(2) = 0.93). These results, along with observations of drought-induced reductions to photosynthesis and growth, support carbon limitation as an important process during mortality of these two conifer species.
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Affiliation(s)
- Lee T Dickman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
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17
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Macalady AK, Bugmann H. Growth-mortality relationships in piñon pine (Pinus edulis) during severe droughts of the past century: shifting processes in space and time. PLoS One 2014; 9:e92770. [PMID: 24786646 PMCID: PMC4008371 DOI: 10.1371/journal.pone.0092770] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 02/25/2014] [Indexed: 01/06/2023] Open
Abstract
The processes leading to drought-associated tree mortality are poorly understood, particularly long-term predisposing factors, memory effects, and variability in mortality processes and thresholds in space and time. We use tree rings from four sites to investigate Pinus edulis mortality during two drought periods in the southwestern USA. We draw on recent sampling and archived collections to (1) analyze P. edulis growth patterns and mortality during the 1950s and 2000s droughts; (2) determine the influence of climate and competition on growth in trees that died and survived; and (3) derive regression models of growth-mortality risk and evaluate their performance across space and time. Recent growth was 53% higher in surviving vs. dying trees, with some sites exhibiting decades-long growth divergences associated with previous drought. Differential growth response to climate partly explained growth differences between live and dead trees, with responses wet/cool conditions most influencing eventual tree status. Competition constrained tree growth, and reduced trees' ability to respond to favorable climate. The best predictors in growth-mortality models included long-term (15-30 year) average growth rate combined with a metric of growth variability and the number of abrupt growth increases over 15 and 10 years, respectively. The most parsimonious models had high discriminatory power (ROC>0.84) and correctly classified ∼ 70% of trees, suggesting that aspects of tree growth, especially over decades, can be powerful predictors of widespread drought-associated die-off. However, model discrimination varied across sites and drought events. Weaker growth-mortality relationships and higher growth at lower survival probabilities for some sites during the 2000s event suggest a shift in mortality processes from longer-term growth-related constraints to shorter-term processes, such as rapid metabolic decline even in vigorous trees due to acute drought stress, and/or increases in the attack rate of both chronically stressed and more vigorous trees by bark beetles.
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Affiliation(s)
- Alison K. Macalady
- University of Arizona, School of Geography and Development and Laboratory of Tree-Ring Research, Tucson, Arizona, United States of America
| | - Harald Bugmann
- Forest Ecology, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
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18
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Poyatos R, Aguadé D, Galiano L, Mencuccini M, Martínez-Vilalta J. Drought-induced defoliation and long periods of near-zero gas exchange play a key role in accentuating metabolic decline of Scots pine. THE NEW PHYTOLOGIST 2013; 200:388-401. [PMID: 23594415 DOI: 10.1111/nph.12278] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 03/18/2013] [Indexed: 05/10/2023]
Abstract
Drought-induced defoliation has recently been associated with the depletion of carbon reserves and increased mortality risk in Scots pine (Pinus sylvestris). We hypothesize that defoliated individuals are more sensitive to drought, implying that potentially higher gas exchange (per unit of leaf area) during wet periods may not compensate for their reduced photosynthetic area. We measured sap flow, needle water potentials and whole-tree hydraulic conductance to analyse the drought responses of co-occurring defoliated and nondefoliated Scots pines in northeast Spain during typical (2010) and extreme (2011) drought conditions. Defoliated Scots pines showed higher sap flow per unit leaf area during spring, but were more sensitive to summer drought, relative to nondefoliated pines. This pattern was associated with a steeper decline in soil-to-leaf hydraulic conductance with drought and an enhanced sensitivity of canopy conductance to soil water availability. Near-homeostasis in midday water potentials was observed across years and defoliation classes, with minimum values of -2.5 MPa. Enhanced sensitivity to drought and prolonged periods of near-zero gas exchange were consistent with low levels of carbohydrate reserves in defoliated trees. Our results support the critical links between defoliation, water and carbon availability, and their key roles in determining tree survival and recovery under drought.
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Affiliation(s)
- Rafael Poyatos
- CREAF, Cerdanyola del Vallès, Bellaterra, Barcelona, 08193, Spain
| | - David Aguadé
- CREAF, Cerdanyola del Vallès, Bellaterra, Barcelona, 08193, Spain
- Universitat Autònoma Barcelona, Cerdanyola del Vallès, Bellaterra, Barcelona, 08193, Spain
| | - Lucía Galiano
- CREAF, Cerdanyola del Vallès, Bellaterra, Barcelona, 08193, Spain
| | - Maurizio Mencuccini
- ICREA at CREAF, Cerdanyola del Vallès, Bellaterra, Barcelona, 08193, Spain
- School of GeoSciences, University of Edinburgh, EH9 3JN, Edinburgh, UK
| | - Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès, Bellaterra, Barcelona, 08193, Spain
- Universitat Autònoma Barcelona, Cerdanyola del Vallès, Bellaterra, Barcelona, 08193, Spain
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19
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Hicke JA, Zeppel MJB. Climate-driven tree mortality: insights from the piñon pine die-off in the United States. THE NEW PHYTOLOGIST 2013; 200:301-303. [PMID: 24050632 DOI: 10.1111/nph.12464] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- Jeffrey A Hicke
- Department of Geography, University of Idaho, Moscow, ID, 83844, USA
| | - Melanie J B Zeppel
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
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20
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López-Hoffman L, Breshears DD, Allen CD, Miller ML. Key landscape ecology metrics for assessing climate change adaptation options: rate of change and patchiness of impacts. Ecosphere 2013. [DOI: 10.1890/es13-00118.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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21
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Eamus D, Boulain N, Cleverly J, Breshears DD. Global change-type drought-induced tree mortality: vapor pressure deficit is more important than temperature per se in causing decline in tree health. Ecol Evol 2013; 3:2711-29. [PMID: 24567834 PMCID: PMC3930053 DOI: 10.1002/ece3.664] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 06/03/2013] [Accepted: 06/04/2013] [Indexed: 11/30/2022] Open
Abstract
Drought-induced tree mortality is occurring across all forested continents and is expected to increase worldwide during the coming century. Regional-scale forest die-off influences terrestrial albedo, carbon and water budgets, and land-surface energy partitioning. Although increased temperatures during drought are widely identified as a critical contributor to exacerbated tree mortality associated with "global-change-type drought", corresponding changes in vapor pressure deficit (D) have rarely been considered explicitly and have not been disaggregated from that of temperature per se. Here, we apply a detailed mechanistic soil-plant-atmosphere model to examine the impacts of drought, increased air temperature (+2°C or +5°C), and increased vapor pressure deficit (D; +1 kPa or +2.5 kPa), singly and in combination, on net primary productivity (NPP) and transpiration and forest responses, especially soil moisture content, leaf water potential, and stomatal conductance. We show that increased D exerts a larger detrimental effect on transpiration and NPP, than increased temperature alone, with or without the imposition of a 3-month drought. Combined with drought, the effect of increased D on NPP was substantially larger than that of drought plus increased temperature. Thus, the number of days when NPP was zero across the 2-year simulation was 13 or 14 days in the control and increased temperature scenarios, but increased to approximately 200 days when D was increased. Drought alone increased the number of days of zero NPP to 88, but drought plus increased temperature did not increase the number of days. In contrast, drought and increased D resulted in the number of days when NPP = 0 increasing to 235 (+1 kPa) or 304 days (+2.5 kPa). We conclude that correct identification of the causes of global change-type mortality events requires explicit consideration of the influence of D as well as its interaction with drought and temperature. This study disaggregates the influence of temperature and vapour pressure deficit on net primary productivity of an Australian woodland and their interactions with drought as potential causal agents in recent widespread forest mortality.
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Affiliation(s)
- Derek Eamus
- Plant Biology and Climate Change Research Cluster, University of Technology SydneyBroadway, PO Box 123, Sydney, New South Wales, 2007, Australia
- National Centre for Groundwater Research and Training, University of Technology SydneyBroadway, PO Box 123, Sydney, New South Wales, 2007, Australia
| | - Nicolas Boulain
- Plant Biology and Climate Change Research Cluster, University of Technology SydneyBroadway, PO Box 123, Sydney, New South Wales, 2007, Australia
| | - James Cleverly
- Plant Biology and Climate Change Research Cluster, University of Technology SydneyBroadway, PO Box 123, Sydney, New South Wales, 2007, Australia
| | - David D Breshears
- School of Natural Resources and the Environment, University of ArizonaTucson, Arizona, 85721
- Department of Ecology and Evolutionary Biology, University of ArizonaTucson, Arizona, 85721
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22
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Elkin C, Gutiérrez AG, Leuzinger S, Manusch C, Temperli C, Rasche L, Bugmann H. A 2 °C warmer world is not safe for ecosystem services in the European Alps. GLOBAL CHANGE BIOLOGY 2013; 19:1827-40. [PMID: 23505061 DOI: 10.1111/gcb.12156] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 01/10/2013] [Indexed: 05/26/2023]
Abstract
Limiting the increase in global average temperature to 2 °C is the objective of international efforts aimed at avoiding dangerous climate impacts. However, the regional response of terrestrial ecosystems and the services that they provide under such a scenario are largely unknown. We focus on mountain forests in the European Alps and evaluate how a range of ecosystem services (ES) are projected to be impacted in a 2 °C warmer world, using four novel regional climate scenarios. We employ three complementary forest models to assess a wide range of ES in two climatically contrasting case study regions. Within each climate scenario we evaluate if and when ES will deviate beyond status quo boundaries that are based on current system variability. Our results suggest that the sensitivity of mountain forest ES to a 2 °C warmer world depends heavily on the current climatic conditions of a region, the strong elevation gradients within a region, and the specific ES in question. Our simulations project that large negative impacts will occur at low and intermediate elevations in initially warm-dry regions, where relatively small climatic shifts result in negative drought-related impacts on forest ES. In contrast, at higher elevations, and in regions that are initially cool-wet, forest ES will be comparatively resistant to a 2 °C warmer world. We also found considerable variation in the vulnerability of forest ES to climate change, with some services such as protection against rockfall and avalanches being sensitive to 2 °C global climate change, but other services such as carbon storage being reasonably resistant. Although our results indicate a heterogeneous response of mountain forest ES to climate change, the projected substantial reduction of some forest ES in dry regions suggests that a 2 °C increase in global mean temperature cannot be seen as a universally 'safe' boundary for the maintenance of mountain forest ES.
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Affiliation(s)
- Ché Elkin
- Swiss Federal Institute of Technology, ETH Zurich, Department of Environmental Systems Science, Forest Ecology, Universitätstrasse 22, Zürich, CH-8092, Switzerland.
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Machumu ME, Yakupitiyage A. Effectiveness of marine protected areas in managing the drivers of ecosystem change: a case of Mnazi Bay Marine Park, Tanzania. AMBIO 2013; 42:369-80. [PMID: 23307198 PMCID: PMC3606699 DOI: 10.1007/s13280-012-0352-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 04/02/2012] [Accepted: 09/11/2012] [Indexed: 06/01/2023]
Abstract
Marine protected areas (MPAs) are being promoted in Tanzania to mitigate the drivers of ecosystem change such as overfishing and other anthropogenic impacts on marine resources. The effectiveness of MPAs in managing those drivers was assessed in three ecological zones, seafront, mangrove, and riverine of Mnazi Bay Marine Park, using Participatory Community Analysis techniques, questionnaire survey, checklist and fishery resource assessment methods. Eleven major drivers of ecosystem change were identified. Resource dependence had a major effect in all ecological zones of the park. The results indicated that the park's legislations/regulations, management procedures, and conservation efforts are reasonably effective in managing its resources. The positive signs accrued from conservation efforts have been realized by the communities in terms of increased catch/income, awareness and compliance. However, some natural and anthropogenic drivers continued to threaten the park's sustainability. Furthermore, implementation of resource use and benefit sharing mechanisms still remained a considerable challenge to be addressed.
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Affiliation(s)
- Milali Ernest Machumu
- Aquaculture and Aquatic Resource Management (AARM) Field of Study, School of Environment Resources and Development (SERD), Asian Institute of Technology (AIT), P.O. Box 4, Klong Luang, Pathumthani 12120 Thailand
| | - Amararatne Yakupitiyage
- Aquaculture and Aquatic Resource Management (AARM) Field of Study, School of Environment Resources and Development (SERD), Asian Institute of Technology (AIT), P.O. Box 4, Klong Luang, Pathumthani 12120 Thailand
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24
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Adams HD, Germino MJ, Breshears DD, Barron-Gafford GA, Guardiola-Claramonte M, Zou CB, Huxman TE. Nonstructural leaf carbohydrate dynamics of Pinus edulis during drought-induced tree mortality reveal role for carbon metabolism in mortality mechanism. THE NEW PHYTOLOGIST 2013; 197:1142-1151. [PMID: 23311898 DOI: 10.1111/nph.12102] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 11/04/2012] [Indexed: 05/04/2023]
Abstract
Vegetation change is expected with global climate change, potentially altering ecosystem function and climate feedbacks. However, causes of plant mortality, which are central to vegetation change, are understudied, and physiological mechanisms remain unclear, particularly the roles of carbon metabolism and xylem function. We report analysis of foliar nonstructural carbohydrates (NSCs) and associated physiology from a previous experiment where earlier drought-induced mortality of Pinus edulis at elevated temperatures was associated with greater cumulative respiration. Here, we predicted faster NSC decline for warmed trees than for ambient-temperature trees. Foliar NSC in droughted trees declined by 30% through mortality and was lower than in watered controls. NSC decline resulted primarily from decreased sugar concentrations. Starch initially declined, and then increased above pre-drought concentrations before mortality. Although temperature did not affect NSC and sugar, starch concentrations ceased declining and increased earlier with higher temperatures. Reduced foliar NSC during lethal drought indicates a carbon metabolism role in mortality mechanism. Although carbohydrates were not completely exhausted at mortality, temperature differences in starch accumulation timing suggest that carbon metabolism changes are associated with time to death. Drought mortality appears to be related to temperature-dependent carbon dynamics concurrent with increasing hydraulic stress in P. edulis and potentially other similar species.
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Affiliation(s)
- Henry D Adams
- Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Biosphere 2, University of Arizona, Tucson, AZ, 85721, USA
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Matthew J Germino
- US Geological Survey, Forest and Rangeland Ecosystem Science Center, Snake River Field Station, 970 Lusk St, Boise, ID, 83706, USA
- Department of Biological Sciences, Idaho State University, Pocatello, ID, 83209, USA
| | - David D Breshears
- Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Biosphere 2, University of Arizona, Tucson, AZ, 85721, USA
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
| | | | | | - Chris B Zou
- Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Travis E Huxman
- Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Biosphere 2, University of Arizona, Tucson, AZ, 85721, USA
- Ecology and Evolutionary Biology, University of California, Irvine, CA, 92617, USA
- Center for Environmental Biology, University of California, Irvine, CA, 92617, USA
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25
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Breshears DD, Adams HD, Eamus D, McDowell NG, Law DJ, Will RE, Williams AP, Zou CB. The critical amplifying role of increasing atmospheric moisture demand on tree mortality and associated regional die-off. FRONTIERS IN PLANT SCIENCE 2013; 4:266. [PMID: 23935600 PMCID: PMC3731633 DOI: 10.3389/fpls.2013.00266] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 07/02/2013] [Indexed: 05/03/2023]
Affiliation(s)
- David D. Breshears
- The School of Natural Resources and the Environment, The University of ArizonaTucson, AZ, USA
- Department of Ecology and Evolutionary Biology, The University of ArizonaTucson, AZ, USA
| | - Henry D. Adams
- Earth and Environmental Sciences Division, Los Alamos National LaboratoryLos Alamos, NM, USA
| | - Derek Eamus
- School of the Environment, University of Technology SydneySydney, NSW, Australia
| | - Nate G. McDowell
- Earth and Environmental Sciences Division, Los Alamos National LaboratoryLos Alamos, NM, USA
| | - Darin J. Law
- The School of Natural Resources and the Environment, The University of ArizonaTucson, AZ, USA
- *Correspondence:
| | - Rodney E. Will
- Department of Natural Resource Ecology and Management, Oklahoma State UniversityStillwater, OK, USA
| | - A. Park Williams
- Earth and Environmental Sciences Division, Los Alamos National LaboratoryLos Alamos, NM, USA
| | - Chris B. Zou
- Department of Natural Resource Ecology and Management, Oklahoma State UniversityStillwater, OK, USA
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Martínez-Vilalta J, Lloret F, Breshears DD. Drought-induced forest decline: causes, scope and implications. Biol Lett 2011; 8:689-91. [PMID: 22171020 DOI: 10.1098/rsbl.2011.1059] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A large number of episodes of forest mortality associated with drought and heat stress have been detected worldwide in recent decades, suggesting that some of the world's forested ecosystems may be already responding to climate change. Here, we summarize a special session titled 'Drought-induced forest decline: causes, scope and implications' within the 12th European Ecological Federation Congress, held in Ávila (Spain) from 25 to 29 September 2011. The session focused on the interacting causes and impacts of die-off episodes at the community and ecosystem levels, and highlighted recent events of drought- and heat-related tree decline, advances in understanding mechanisms and in predicting mortality events, and diverse consequences of forest decline. Talks and subsequent discussion noted a potentially important role of carbon that may be interrelated with plant hydraulics in the multi-faceted process leading to drought-induced mortality; a substantial and yet understudied capacity of many forests to cope with extreme climatic events; and the difficulty of separating climate effects from other anthropogenic changes currently shaping forest dynamics in many regions of the Earth. The need for standard protocols and multi-level monitoring programmes to track the spatio-temporal scope of forest decline globally was emphasized as critical for addressing this emerging environmental issue.
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Affiliation(s)
- Jordi Martínez-Vilalta
- CREAF/Unitat d'Ecologia, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
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